1. Field of the Invention
The present invention relates to a torsional molding apparatus for arranging each crank pin of a crank shaft at a predetermined angular position wherein a plurality of crank pins are arranged on the same plane passing through an axis of the crank shaft.
2. Description of the Prior Art
In conventional torsional molding apparatuses of the above type, a crank shaft is clamped between clamp arms or split molds for torsional molding. These apparatuses are, however, used only for torsion operation and have a large size. A torsional force is obtained by a cylinder or the like means provided separately from a driving source for clamping operation, and therefore, the structure inevitably becomes complicated.